A new topographic pattern for early differentiation of pellucid marginal degeneration from keratoconus

Session Details

Session Title: Cornea
Session Date/Time: Friday 09/02/2018 | 08:30-10:00
Paper Time: 09:15
Venue: Annex A

First Author: M.Jafarinasab IRAN
Co Author(s): D. Najdi  S. Feizi              

Abstract Details

Purpose:

To introduce a new topographic sign which can help to early discriminate pellucid marginal degeneration (PMD) from keratoconus (KCN).

Setting:

Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran Department of Ophthalmology,Labbafinejad Hospital,Shahid Beheshti University of Medical Sciences, Tehran, Iran.

Methods:

This cross-sectional study consisted of 20 patients with bilateral but asymmetric PMD; one eye had early form of disease whereas, PMD was more advanced in the fellow eye. Computerized corneal topography and dual-Scheimpflug analyzer were performed in these eyes. Topographic pattern and indices were analyzed to differentiate the early stage of PMD from KCN.

Results:

Based on the corneal topography and tomography the diagnosis of PMD was equivocal in one eye but clear in the fellow eye with the more advanced disease. We could describe a topographic pattern which was useful in discriminating early PMD in 90% of the eyes. This pattern which looked like an apple (apple sign) constantly had two portions; a flat stem and a steep core portion. The flat portion was located in the superior part of the map with an extension from 45 to 135 degrees.

Conclusions:

The apple pattern observed in corneal topographic map, especially in sagittal and instantaneous map, is a useful sign for the early diagnosis of PMD. Changes of steep and flat areas inside the apple pattern is a good indication of disease progression. A prospective study is now underway to confirm the clinical implications of this pattern.

Financial Disclosure:

None